Fluid-Structure Interaction of Human Upper Airways

Sammanfattning

This thesis investigates the fluid-structure interaction (FSI) of a Starling Resistor tounderstand the mechanics behind wheezing, which is a common respiratory symptom.By using a combination of computational fluid dynamics (CFD) and structuralanalysis, the study applies a partitioned FSI approach to simulate the interactionbetween airflow and a Starling Resistor. The results of this study present the firstvalid FSI simulation that models wheezing. In addition, the research investigateshow changes in the shape of airways, particularly narrowing in the middle part,affect the flow speed and distribution of pressure. The simulations show how airmoves and how the structures change, capture the frequency of the onset of tube’soscillations. The results suggest that the increase in pressure at the inlet of thetube in combination with the external pressure that act on the tube, is the primarymechanism causing the tube’s oscillations. This study provides valuable insightsinto how fluids and structures interact in collapsible airways and contributes to thebroader field of respiratory mechanics, especially for wheezing. The results couldhelp in developing better tools for diagnosis and strategies for treating respiratoryconditions. Also, future work could focus on improving the simulation models by usingmore advanced mesh designs, models that account for turbulent flow, finer timesteps to accurately capture the exact start and frequency of tube movement andan improvement of signal processing to analyze the tube oscillations with a waveletprocess. These improvements could lead to more precise and predictive models,ultimately benefiting both clinical practice and patient diagnoses.